Research

Recent years, the alpine grasslands on Tibetan Plateau are suffering from quite severe degradation. Serious grassland degradation is endangering eco-environment of this region. The degraded grassland occupied about one third area of the all investigated grasslands on the Tibetan Plateau, and the current productivity of plateau grasslands was about 30% less than the productivity measured only two decades ago. At the same time, the native fauna of the Tibetan Plateau has been greatly reduced, and nearly every medium-to-large mammal species is now classified as threatened. It has become increasingly clear that the alpine grassland ecosystem on Tibetan Plateau is in danger of losing much of its native species, breaking the balance of grasslands ecology, and its ability to support sustainable pastoralism, the region's primary economic activity. 

●　  Alpine Grassland Degradation

Alpine grassland degradation is a process of reversing succession. It always has the sequence as follows: non-degraded grassland → lightly degraded grassland → moderately degraded grassland → heavily degraded grassland. According to the relative value of above-ground biomass, plant coverage, proportion of palatable herbage and soil hardness, all grasslands is divided into 4 phases as which are non-degraded grassland, lightly degraded grassland, moderately degraded grassland, and heavily degraded grassland, respectively. In summary, with the degradation extent from light to heavy, above-ground biomass, plant coverage, proportion of palatable herbage, and soil hardness will decrease as well as soil moisture, organic matter content of the soil. Plant diversity and richness index had decreasing trends from non-degraded grassland to heavily degraded grassland with the method of principal component analysis.
There was about 4251.10×104 ha degraded grassland, 32.69 % area of the all investigated grassland on Tibetan Plateau. Heavily degraded grasslands covered an area of 703.19 ×104 ha, about 16.54% of degraded grassland, and were also related to the winter and spring pastures, mainly at the places of Tibet, Qinghai, and Gannan. Grassland degrading speed in the past 10 years was increased from 3.9 % in 1970s to 7.6 % in 1990s at the headwater of three rivers. However, the degrading trend of alpine grassland is still not reversed.